Incident Overview
On 5 December 2003 at 1015Z, a Piper PA-32-260, registration ZS-ELX, experienced an engine fire during start-up on the apron at Upington Aerodrome. The flight was a private operation with two persons on board. No injuries or fatalities were reported. The weather conditions were clear with visibility greater than 10 km, a north westerly wind at 10 knots, and a high ambient temperature of 43°C.
Sequence of Events
The pilot had departed from Cape Town Aerodrome and landed at Upington Aerodrome to refuel en route to Mossel Bay. After the aircraft was refueled to capacity, the pilot initiated the start-up procedure for the continuation of the flight. During start-up, an engine fire started. The pilot responded by selecting the master switch to the off position and vacating the aircraft. Aerodrome personnel then assisted in extinguishing the fire using portable fire extinguishers, successfully limiting the fire to the engine nacelle area.
Damage Assessment
The aircraft sustained fire damage limited to the electrical wiring and ignition harness within the engine nacelle area. The cowlings were slightly burnt and various wires showed signs of fire damage.
Probable Cause
The pilot confirmed to the Approved Maintenance Organisation (AMO) that he had over-primed the engine. This resulted in excess fuel accumulating in the manifold and lower cowling, which ignited upon starting the engine. The high ambient temperature of 43°C was a contributing factor, as it may have increased the volatility of the fuel and reduced the margin for error during start-up.